1. Field of the Invention
The present invention is directed to a method and a system for controlling at least one triggering element for passenger protection means.
2. Description of the Related Art
When igniting igniters for passenger protection means such as airbags, they often form arcs and thus short circuits to conductors or auto body parts during the explosion. This manifests itself in a change in the resistance value of the igniter during the ignition. Due to this load change, an output stage of such an ignition system provides very high ignition currents, some of which have up to 10 times the magnitude of the typical ignition current.
Published German Patent Application DE 10 2009 027 918 A1 describes, for example, a system and a method for controlling at least one triggering element for passenger protection means. The described system includes a high-side circuit which establishes a first connection from an energy source to the at least one triggering element, and a low-side circuit which establishes a second connection from the at least one triggering element to ground. In addition, a regulating system is provided which regulates a triggering current for the at least one triggering element, the regulating system being associated with the high-side circuit and/or the low-side circuit. In addition, the high-side circuit and the low-side circuit each have two output stages per triggering element connected in parallel for regulating the triggering current, at least one of the at least two output stages having a current regulating system and one or multiple transistors connected in parallel. The parallelization of the output stages makes it possible to demonstrate scaling, i.e., higher or longer triggering current pulses are implemented using two or more output stages connected in parallel. The triggering current pulses result in the ignition of an explosive charge or the magnetic actuation of a passenger protection means.
Published German Patent Application DE 10 2005 055 068 A1, for example, describes a device for controlling an ignition element. The described device includes two ignition current measuring devices, each of which measures an ignition current and compares it with particular thresholds. In addition, the ignition current measuring devices determine the particular times for which the ignition current is above each threshold.
Furthermore, the described device includes an ignition current limitation which is associated with at least one ignition switch and is adjustable to at least two different current levels. In addition, the described device includes at least two ignition time measuring devices which release each ignition switch for a particular ignition interval, one of the at least two ignition time measuring devices adjusting the current limitation.